The present invention relates to devices for navigation, and more particularly, to a navigational aid designed to enable a private aircraft pilot to more easily determine his or her position.
The Federal Aviation Administration (FAA) has established a system of beacons installed all across the United States called VOR beacons. VOR stands for "VHF omni directional receiver" and refers to the receiver on an aircraft that picks up a radial carrier wave from a beacon as it sweeps through three hundred and sixty degrees. Thus, a pilot knows what beacon he or she is receiving and what radius his or her aircraft is located is on. By using two different beacons and triangulating, the pilot can get a position fix.
The FAA disseminates maps that have VOR compass rose markings pre-printed around each beacon, which are rings imprinted on the maps with compass numbers on the same. While flying solo, it is difficult for a pilot to find these rings because the maps have so many other crowded markings and the ink is not very visible. It is further difficult for a pilot to mark out the correct triangulation lines to determine his or her position. This is usually done with a ruler and a pencil.
U.S. Pat. No. 3,387,372 of Sabadishin discloses a lap held plotting board including a pair of transparent plastic compass roses which are pinned to a map supported on the board. The board is made of laminations of cork, paper and MASONITE. A linear scale is mounted to each compass rose for rotation about the axis of its mounting pin. Each compass rose has a dish configuration which is deflected to establish sufficient frictional force with the map to prevent rotation of the rose during rotation of the linear scale connected thereto.
U.S. Pat. No. 3,881,253 of Haws shows a similar arrangement except that the roses are held by suction cups to a clear plastic panel overlying the map.
U.S. Pat. No. 2,736,096 of Greene shows a radio plotter including a pair of round compass portions 10 each with a projecting arm 12. As is best apparent from FIGS. 2 and 3, and column 3, lines 18-46, a separate thin metal disk 21 with a central pin 22 has a layer of adhesive 25 on the upper surface thereof. The pin 22/23 is pushed through the map or chart from the reverse side thereof so that the adhesive 25 bonds the disk 21 to the reverse side of the map. A combination compass/arm A is then connected to the pin on the front side of the map for rotation in the plane thereof. Head portion 23 of the pin 22 snaps through a hole 26 in the compass portion 10.
U.S. Pat. No. 3,187,434 of Casagrande discloses another marine navigation plotting device in which a map is mounted between two pieces of PLEXIGLASS plate. Holes are drilled through the plates at the location of the broadcast antennas. Slotted protractor arms 14, 15 and 16 are pivotally connected to the plates by thumb screws 24, 26 and 28 which are inserted through the slots in the arms and threaded into the holes drilled in the plates.
U.S. Pat. Nos. 3,281,942; 3,690,009; 3,813,783; 3,844,042; 4,095,342; and 4,359,628 show other related map navigational aids. Some of these, such as the Preuit and Henley, III devices, can be pinned to a map while others, such as the Hodge, Price and Lambert devices, are simply laid on top of a map.
While the foregoing patented devices can facilitate navigation to varying degrees, they are generally too complex and cumbersome to be used by a typical private pilot flying solo. Such a pilot must spend as much time as possible obeying the "see and be seen" rule of flying and therefore cannot afford to spend a great deal of time looking down at a map and manipulating various navigational rulers, etc. Furthermore, a number of the patented devices require extensive set up and entail the use of large boards which are cumbersome to have in the cramped cockpit of a small plane. In addition, the FAA regularly updates aerial maps. FAA regulations require that all pilots use the latest maps. Accordingly, many of the patented devices that require extensive set up must be repeatedly shifted to new maps. The devices themselves are generally too expensive to discard each time a new map is issued.